Global energy usage continues to rise with no sign of abatement, creating a growing demand for oil resources. Light, sweet crude oil production is not increasing enough to meet this growing demand. Additionally, the reserves of light, sweet crude oil are being depleted more rapidly than new reserves are being found. To fill this gap, larger quantities of heavy oil feedstocks such as heavy crude oils or extra heavy crude oils derived from various carbonaceous resources are being brought on stream. The cost of development of these heavy crude oil resources has been decreasing over the last several decades making them more economical to recover.
Heavy crudes often require some processing to reduce their viscosity and to make them pumpable. Several processes which may be used for this purpose include partial upgrading by hydroprocessing, by coking or by blending the heavy crude with light hydrocarbons. Additives may also be used. Another alternative for handling heavy crude is to form an oil-in-water emulsion, optionally with the addition of additives to reduce the crude's viscosity. All of these processes create a pumpable generic type syncrude suitable for refinery processing. However, the economics of processing these pumpable generic type syncrudes are prohibitively expensive, because of the low conversion rates of the heavy crude oil resources.
U.S. Pat. No. 3,369,992 discloses a distillate low pour point synthetic crude oil produced from a virgin distillate and a reduced crude from a high wax content and high pour point crude. This synthetic crude is formed by mixing the virgin distillate with a fraction obtained by coking the reduced crude. The coker overhead volatile product is fractionated into a heavy stream for recycle to the coker and a distillate fraction which is recovered as a low pour point synthetic crude.
U.S. Pat. No. 4,454,023 discloses a process, including visbreaking, distillation, and solvent extraction for rendering a heavy viscous crude pumpable.
U.S. Pat. No. 5,233,109 discloses a synthetic crude produced by catalytically cracking a biomass material comprising a plant oil and/or an animal oil and/or a rubber material.
U.S. Pat. No. 6,016,868 discloses an integrated process for treating production fluids to form a synthetic crude oil. The production fluids are recovered from the application of in situ hydrovisbreaking of heavy crudes and natural bitumen deposited in subsurface formations.
U.S. Patent Application Publication 2004/0164001 A1 discloses a business process that monetizes bitumen reserves utilizing proven refining processes to ultimately produce high quality refined oil products.
Additional disclosures relating to the preparation of a syncrude are taught in U.S. Pat. Nos. 5,968,991; 5,945,459; 5,856,261; 5,856,260; 5,863,856 and 5,292,989.
While some processes have been proposed to reduce the viscosity of a crude, none have been offered for producing a synthetic crude which is tailored for the current needs of a particular refinery. Furthermore, no process has been described for producing a synthetic crude which comprises vacuum gas oil or lighter fractions.